Waterproof, durable products made from recycled rubber products

ABSTRACT

Synthetic roofing products such as simulated slate and clay tile shingles, and other products, such as flower pots, floor coverings, plastic pallets and the like are compression molded from a mixture of ultra low density polyethylene binder and a filler which may comprise recycled rubber products such as E.D.P.M (ethylene propylene diene monomer) and S.B.R. (styrene butadiene rubber). Colorants may be added to the mixture prior to final molding. Many of the products, especially synthetic shingles, are less expensive, easier to handle, and more durable than the slate or clay tile shingle product simulated.

This application is a continuation-in-part of U.S. Ser. No. 09/579,988filed May 26, 2000, now U.S. Pat. No. 6,168,205.

DESCRIPTION OF THE RELATED ART

U.S. Pat. Nos. 5,086,552, 5,675,954 and 5,873,208 are directed to theuse of old vehicle tires which are cut into various shingle shapes andapplied directly as a roofing material. Although inexpensive, theseproducts have a limited market because they are not aestheticallypleasing.

U.S. Pat. No. 5,648,144 issued in 1997 to Maurer, et al is directed to asynthetic slate roofing-material which comprises a resin matrix andwhich employs inert fillers such as A.T.H. (aluminum tri-hydrate),Commercially available solid surfacing materials may be used along withadditives and colorants in the final mix prior to homogenizing andmolding. It is believed that the use of a resin binder greatly limitsthe flexibility of the synthetic slate roofing material described above.

Recently, James Crowe, Hamilton, Ontario, Canada, appeared on PBS's“THIS OLD HOUSE”. Mr. Crowe showed and described a synthetic slateshingle which he said he invented in 1988. The shingle includespelletized materials such as surplus rubber from from a plant whichmakes rubber products and surplus polyethylene and polypropylene from adisposable baby diaper plant. Although Crowe states that his binders aretrade secrets, they are believed to be vinyl acetate and aluminumtrihydrate. The content of binder in Crowe's product is thought to beabout 60% by weight, and his rubber filler materials, about 40% byweight. By contrast, the subject invention employs up to about 60% byweight of rubber filler materials, and only 40% by weight binder. Theultra low density polyethylene binder employed by applicant is verypliable. It is capable of 1000% elongation, and acts like rubber, and isvery tough.

DETAILED DESCRIPTION OF THE INVENTION EXAMPLE 1

The Spanish replica tile is molded from the following composition:

E,P,D,M, (ethylene propylene diene monomers) scrap from rubber seals orcar parts and

S.B.R. (styrene butadiene rubber)—up to @50% by weight;

Elastomeric binders, E.V.A. (ethylene vinyl acetate) and U.L.D.P.E.(Ultra low density polyethylene)*

@10-20% by weight, preferably @15% by weight;

Fire retardant, A.T.H. (Aluminum tri-hydrate)

@20% by weight,—obtain “C” rating fire retardancy,

@35% by weight,—for “A” rating fire retardancy, in combination with @ 4%by weight zinc oxide;

H.D.P.E. (High density polyethylene)

@10-30% by weight, presently @25% by weight, and preferably, @20% byweight.

*the presently preferred U.L.D.P.E. is available from du Pont under thetrademark, “Engage”.

The above materials are blended together (adding the liquids to thesolids) at a temperature in the range of 280 to 350 deg. F., preferably300 deg. F. to form an homogeneous blend having the consistency offreshly mixed putty. The desired coloring, in this case a red claycoloring, is added at the time of blending, and mixing is continueduntil the blend is the desired color. The mixture is then passed througha 4-6 inch hydraulic extruder at a temperature below 350 deg. F. Theextruded mass is then placed in a water cooled compression mold, andmolded into the final product at a temperature in the range of 160-325deg. F. The resulting Spanish replica tile is about ⅓ the weight of aSpanish clay tile, and is practically unbreakable and indestructible.The product is fire retardant and is believed to have a useful life muchgreater than the product it replaces. In addition, installation is muchsimpler and less expensive, and does not require specially skilled tilecutters. There should be no breakage losses during installation.

Other fire retardants may be used instead of ATH. These include“Plastisan B” made by 3V Corp., Georgetown, S.C.; “Phos-check”,available from Solutia Corp., St, Louis, Mo.; and “Dover-phos-9228” madeby Dover Chemical, Dover, Ohio. The amount of fire retardant used isdetermined by the fire retardant rating required.

EXAMPLE 2

The slate replica roofing material is manufactured from about the sameformulation as employed in Example 1, but a little less H.D.P.E. is usedto make the product slightly more flexible. Instead of red coloring, agray slate coloring may be added. The slate replica roofing material isabout ⅓rd the weight of the natural slate product, and is practicallyunbreakable and indestructible. The product is hail-resistant, and isexpected to have a much greater useful life than the natural slateproduct it replaces. The slate shingle is made in a standard sizewithout any loss in the manufacturing process, which is the case with anatural slate shingle due to irregularities in the slate. Making naturalslate shingles is very labor intensive and costly.

Installation of the replica slate shingle is much simpler and lessexpensive, and does not require special installation tools and speciallyskilled slate cutters. There is no breakage loss during installation.

EXAMPLE 3

The Italian replica roofing material is also manufactured from about thesame formulation as set forth in Example 1. Since this roofing materialis similar to the Spanish replica tile in desired rigidity, the formulais about the same as set forth in Example 1 above. Coloring is a matterof choice, and the molded Italian replica tile weighs about ⅓rd lessthan the natural Italian tile presently in use. Cost for the replicatile is estimated to be about ⅓rd the cost of the presently used, terracotta tiles. The replica tile is also practically unbreakable andindestructible. It is much easier to install, and does not requirespecial tools or specially skilled installers.

EXAMPLE 4

Flooring materials may also be made using the recycled crumb materialsof the invention. For flooring materials, it is preferred that apolyolefin elastomer (H.D.P.E., high density polyethylene) recycledcrumb rubber be used as the principal ingredient. Any desired size,thickness, shape, resiliency and color of flooring materials may be madeby slight modification of the ingredients. A floor tile can be madesimulating the appearance and texture of marble, slate, brick or otherstone, and it can be adapted to the injection molding process describedabove. Larger floor coverings in sheet-like shapes may be made usingconventional technology for sheet-forming from thermoplastic blends.

Coloring

The preferred binder of the invention is U.L.P.E. (ultra low densitypolyethylene) available from du Pont under the trademark “Engage”. Thisbinder comes in many colors, and the particular color, or combination ofcolors, may be selected to provide the desired color of the finishedproduct. This binder also comes in “clear”, and, in that case, colorconcentrates for paints and plastic can be used in the extrudate mixused to make the final product. Such color concentrates are commerciallyavailable, and one source is Bayer AKTG. Either a powder or a liquidcolor concentrate may be used. One surprising discovery is that up toabout 20% by weight black rubber crumb can be used in combination witheither the clear U.L.P.E. or the colored U.L.P.E. without influencingthe final product color.

Recycled Filler Material

Both E.P.D.M. (ethylene propylene diamine monomer) and S.B.R. (styrenebutadiene rubber, from shredded vehicle tires) are excellent fillermaterials in the molded products of the invention, and are typicallyobtained by recycling waste materials which would otherwise go toalready full land fills. U.S. Pat. No. 5,927,627 issued Jul. 27, 1999shows equipment and a method for obtaining rubber crumb from such wastematerials as steel-belted vehicle tires, rubber seals and auto parts.Such filler materials have already been “vulcanized”, so they are fireretardant. They are relatively inexpensive, water repellant and hightemperature resistant, so they are especially suitable for use inroofing materials (shingles), floor coverings (tiles and sheetmaterial), flower pots and utility containers. Other filler materialscould also be used to replace all or a part of the preferred materials.Such replacement materials must have the needed properties, especiallywater and heat resistance.

Other Equivalent Materials and Temperatures Utilized

While particular percentages of materials and particular temperatureranges have been disclosed herein, it is intended in this specificationto include all equivalent materials and temperature ranges which wouldoccur to those of skill in the art via reasonable experimentation withthe compounds and processes disclosed herein.

For example, L.D.P.E.(Low density polyethylene) materials may beincluded in the formulae described and still fall within the intendedbroad scope of the invention.

As an example of the above, to achieve the highest fire and hailratings, the following formula may be utilized for a slate replicashingle:

ATH or Mag hydrox - - - 45%

ULDPE and/or EVA - - - 25%

HDPE - - - 15%

LDPE - - - 15%

with the above formula to include a small amount of color.

As an example of the varied temperatures used in practice of theinvention, the “blended together” temperature may be in the range of280-380 degrees F. The extrusion temperature may be below 380 degrees F.The temperatures used in the compression molding step may be in therange of 250-380 degrees F.

The above formula and temperatures illustrate optimal materials andtemperatures and it is intended to broadly cover all equivalent designsand uses.

The invention is further defined by the claims appended hereto.

What is claimed is:
 1. A slate replica roofing shingle compressionmolded from a mixture of: about 20-40% by weight ethylene propylenediene monomer scrap from rubber seals and car parts and vulcanizedstyrene butadiene rubber; about 10-30% by weight elastomeric binderscomprising a mixture of ethylene vinyl acetate and ultra low densitypolyethylene; about 20-40% by weight fire retardant; and about 10-30% byweight high density poly-ethylene; to obtain a flexible slate replicashingle which is waterproof, weather resistant, hail resistant, andsimple to install, arid is substantially impervious, wherein the mixtureis passed through a hydraulic extruder at a temperature below 350 degresF. and then placed in a water cooled compression mold and molded intothe final product at a temperature in the range of 160-325 degrees F.